Air cushion fitting for thermal systems



Nov. 5, 1940'. E. s. CORNELL, JR 2,220,079

AIR CUSHION FITTING FOR THERMAL SYSTEMS Filed Oct. 28, 1937 3 Sheets-Sheet 1 Ti l.

INVENTOR Edwrol 5. Cornell ,Jr.

Nov. 5, 1940. v E. s. CORNELL. JR 2,220,079

AIR CUSHION FITTING FOR THERMAL SYSTEMS v Filed Oct. 23, 1937 3 Shets-Sheet 2 v v s INVENTOR Edwa cl 5. CornelLJr. K5 HIS v ORNEY 1940. I s, CORNELL. JR 2,220,079

AIR CUSHION FITTING FOR THERMAL SYSTEMS Filed Oct. 28/1957 5 Sheets-Sheet a T534. Q A

INVENTOR Edward 5 CornglLJr.

@13 HlS ORNEY Patented Nov. 5, 1940 UNITED STATES PATENT OFFICE AIR CUSHION FITTING FOR THERMAL SYSTEMS 4 2 Claims.

This invention relates to air-cushion fittings for thermal systems.

The invention finds particular application in a liquid circulating system of the nature of a closed-tank type of heating system embodying the circulation of heated water, and most preferably employing a pump or similar device for circulating the heated water through the mains and radiators of the system. Such a system, incorporating the present invention, is set forth and claimed in my presently co-pending application Serial No. 171,539, filed October 28, 1937, entitled Closed thermal system.

It is an object of the present invention to provide means whereby a relatively small volume of air or other gas is entrapped within a novel fitting to form a gas cushion for the heating system. It is a feature of the invention that the entrapment means interposes an air or gas cushion of comparatively small volume directly in the path of the circulating liquid, the cushion being further characterized by its relatively great area of contact with the liquid.

Pursuant to the present invention, the air or gas cushion-forming means may comprise a unitary fitting having a flow-passage therethrough of general S-shaped or equivalent serpentine configuration, the initial loop of such passage being enlarged to form a gas-entrapping chamber of adequate volume. The inlet and outlet termini of the fitting may be provided with screw-threaded or equivalent connection means whereby the fitting may be installed in the piping system. Under typical conditions of employment of the present invention, the fitting is connected to a vertical outflow-main of the boiler of a hot water heating system, and most preferably is immediately adjacent the boiler, the inlet portion of the stated serpentine passage thus forming a direct continuation of the vertically-rising boiler mam.

The serpentine passage through the fitting is advantageously formed by oppositely extending 'and spaced-apart septa extending from wall to of the gas cushion equal in area to the sum of the areas of the respective passages.

A gage-glass and an air venting means may be employed with the gas entrapping chamber to provide a positive method of regulating the volume of the gas cushion and the position and the area of its free surface; however, the configuration and volume of the air chamber per se may be such that the residual air or other gas remaining in the system after the liberation of the greater portion through the radiators or other air release means will, Without further adjustrnent, be of adequate volume to serve efiiciently as a cushioning element.

In the accompanying drawings:

Fig. 1 is a representation of a closed circuit hot water heating system employing my invention;

Fig. 2 is a sectional elevation of one embodiment of my invention;

, Fig. 3 is a plan view of the embodiment of Fig. 2; and

Fig. 4 is a vertical sectional view of another embodiment of the present invention.

Fig. 5 is a plan view of the structure of Fig. 4.

Referring toFigure l, a heating system of the closed circuit hot water type more fully set forth and claimed in my stated co-pending application,

includes a boiler Hi, supply main 12, return main l4, heating-unit supply risers l6, l6, heat eX- changers ll, H, and return risers l8, IS, the piping arrangement thereby forming a complete circuit in which heated water is conveyed to the heat exchangers and the cooled water therefrom returned to the boiler. A water circulator 20, or other positivepumping means, may be installed in the return main, usually adjacent the boiler, as shown. The operation of such circulator may be controlled by a conventional room thermostat 22 forming a thermo-responsive make-and-break switch in the electrical circuit 24.

Water may be supplied to the boiler I!) through the feed line 26, in which there also may be installed a manually operated control valve 28, a pressure reducing valve 30 and a pressure relief valve 32, the latter serving to discharge Water through its associated vent pipe 33 in the circumstance of an abnormal pressure condition within the system. As indicated, the feed line 26 is connected into the return main I4 at a point closely adjacent the boiler.

The auxiliary thermal system, including a heat exchanger 36, may be. arranged to heat water for storage in .a tank 38. In accordance with I the heat exchanger 36, the said coil being connected as by piping 31 to the storage tank.

As indicated in Figure 1, there is installed intermediate the Vertical outflow main lZa of the boiler l0 and supply main I2 an air cushion fitting 4B, which functions to interpose an air or gas cushion of relatively small volume but relatively great free surface directly in the path of flow of Water through the piping system. The stated air cushion provides means whereby the conventional closed type expansion tank may beeliminated, and additionally affords means for absorbing surges, shocks, and/or sound-wave vibrations and thus prevent or limit their transmittal through the heating system.

The fitting 46, forming the subject matter of the present invention may be a cast structure, of iron, brass or equivalent metal. A serpentine passage through the fitting may be formed by the spaced apart and oppositely disposed overlapping septa 4|, 42, extending from wall to wall of the fitting. The passage, see Fig. 2, comprises an inflow passage 44, an outflow passage and an intermediary connecting passage 46, the direction of flow through successive passages being preferably fully reversed.

. In accordance with preferred practice, the fitting 46 is located closely adjacent the boiler, and thus the inflow passage 4| effects a continuation of the customary vertical riser I2a of the boiler. Inflow and outlet connections 43, 43a are arranged for direct piping connection. The entire passage advantageously has a flow capacity equivalent to or greater than the riser 12a, to aiford full and unrestricted flow through the fitting.

To reduce the number of sizes of the fittings 40, and thus facilitate warehousing and commercial distribution, one size of fitting may be adapted for use with a suitable number of smaller sizes of riser l2a by suitably bushing the inflow and outflow connection points.

As indicated in Fig. 2, the inflow and outflow connections may have conventional pipe-threading; obviously flanged or union connections may be provided. A plug 41, with which there may be employed a packing washer 48, may form a convenient drain or clean-out port.

In conformity with a principle of this invention, namely, the interposition of a gaseous cushion directly in the path of water flow in the system, said cushion being of relatively small volume, but having a relatively great free surface in direct contact with the flowing liquid, the initial loop-of the serpentine passage may be enlarged to form a suitable bell-like chamber 50 of requisite volume. Thus, the free surface of the gas entrapped in the bell directly intercepts either a normal flow of water through passage 44, or a reverse flow through passage 46. Also, the. area of free surface of the gas chamber, comprising the total of the horizontal areas of passages 44 and 46, presents an exceptionally large flexible cushioning surface.

Referring to Fig. 4, a second'form of air cushion fitting 40 may be generally similar in structure to that of Figs. 2 and 3, and may be provided with a gage-glass assembly 55, and means such as the vent valve 56 for releasing air or gas trapped within its gas cushion chamber 50 for positively regulating the volume of gas cushion within the gas chamber, and the area of the cushion in contact with the thermal liquid. It is to be noted also that .a tappedboss 5.1.may be.

provided at the crown of the gas chamber 50 to accommodate a piping connection for the purpose of utilizing an auxiliary air chamber; but otherwise is closed by a suitable plug or the like, to confine the gas chamber within the fitting per se. It will of course be obvious that the structure of Fig. 2 may also be provided with such auxiliary gas chamber connecting means, gage glass assembly and air vent.

The air-cushion fitting may be provided, preferably in the outflow leg thereof, with self-closing valve means for controlling, inclusive of precluding, thermo-syphonic flow of water through the system, such preclusion of flow being advantageous when it is neither desirable nor necessary to supply heat to the exchangers ll of the heating system. Such an arrangement permits the auxiliary system for heating water for domestic use to function entirely independently of the main heating system.

The valve structure, which may be identical for the embodiments of Figs. 2 and 4, may include a weighted valve disc or equivalent 66,.secured as by the cotter pin 6! to a tongue 62, the latter being free to pivot on a pin 63 suitably contained within a suitable housing 64. In completion of the valve structure, there is provided a preferably upwardly sloping valve seat 65, which may be cast integrally with the fitting, as indicated in Figs. 2 and 4, or, in accordance with other practice, may be a removable seat ring.

As indicated in .Fig. 3', a set screw 66 may have a suitably drilled central opening 61 to accommodate an end of pin 63; screw 66 thus serves as a removable supporting structure for the pin 63.

Passage v45 is thus normally closed, the Weight of disc 66 urging it into valve closing position against seat 65.. In the application of the present invention to, a hot water heating system as aforesaid, the weight of disc is preferably of such value that thermo-syphonic pressure generated by the boiler is insufiicient to overcome the resistance of valve disc 60, and thus thermo-syphonic circulation through the system may be positively prevented. Under the pressure generated by a suitable circulation pump, however, the valve will open and permit enforced circulation of heated water through the system. I

To permit an adjustment of the degree of closing of the valve disc 60, and thereby to provide means for holding the disc 60 open in any position, there is provided an adjustment screw 68, which is arranged to bear against the ear 69 formed preferably integrally with the tongue 62.

Suitable packing Ill and'packing nut H are advantageously employed to provide a water-tight seal for the screw 68.

As is well understood, the pipe size of the vertical outflow riser Fla is established in accordance with the thermal output of the heating system and the length and similar characteristics of the piping per se. The size of such outflow riser is thus in proportion to the total volume of liquid contained in the heating system, and in pelled from the system by the manipulation of conventional air release cocks 15. A residual volume of gas will remain entrapped by the bell 50, since at a certain stage of operation an adequate water-flow passage will be created between the surface of the gas pocket and the upper terminus of tongue 4|, the said gas surface thus defining a boundary of the water flow passage. Such gas-water line position is indicated by the line AA of Fig. 2.

It will be apparent that the velocity and pressure of circulation generated solely by thermosyphonic circulation, as in an installation not employing a circulator 20, may not be adequate to force air through and out of the gas cushion fitting, and thus the volume of air remaining entrapped in the gas chamber may be excessive.

- The embodiment of Fig. 4 finds particular application in such an installation because gas may be vented from its chamber 50 by manipulation of the vent valve 56. The volume of gas in the chamber may be established in that manner, gage glass 55 showing the water level in the chamber.

Assuming thermo-syphonic circulation, however, it will be apparent that the valve disc 60 must be held in full open position, to permit water circulation through the heating system. When it is neither desirable nor required to circulate heated water to the, room heating exchangers as during the summer months when the auxiliary water heating system remains in full operative status to heat water for domestic purposes, suitable manipulation of adjustment screw 68 permits the full closure of the valve.

Advantageously, the valve seat is inclined in the direction of flow of the thermal liquid. An angle of inclination yielding satisfactory results, is indicated in Figs. 2 and 4 of the drawings of the instant application. Among the advantages gained are, minimum deviation of the paths of flow of the thermal liquid, effective at the instant of first opening of the valve, and the at-' tainment from fully closed valve position to fully open valve position effected by minimum angular arc of movement of the valve.

Whereas, I have described my invention by reference to specific forms thereof, it will be understood that many changes and modifications may be made without departing from the spirit of the invention.

Iclaim:

1. Air cushioning means for a thermal system utilizing water as the thermal medium, comprising a hollowbody, opening means for the inflow of water disposed toward the bottom and adjacent one end of the hollow body, a septum disposed interiorly of the hollow body extending uninterruptedly from the bttom of the hollow' said opposite lateral sides of the hollow body and terminating at a level below the stated level of the first-named septum, thereby providing a space within the upper interior of the hollow body above the stated level of the first-named septum for the entrapment therein of air under pressure, the free level of which and the stated two septa define a serpentine path of flow of the water under pressure, and opening means disposed adjacent said remote end of the hollow body for the outflow of the water.

2. Air cushioning means for a thermal system utilizing water as the thermal medium, comprising a hollow body, opening means for the inflow of water disposed toward the bottom and adjacent one end of the hollow body, a septum disposed interiorly of the hollow body extending uninterruptedly from the bottom of the hollow body and uninterruptedly from the opposite lateral sides of the hollow body and terminating at a level less than the height of the interior of the hollow body, a septum spaced from the first-named septum in direction toward the end of the hollow body remote from said one end and disposed interiorly of'the hollow body and extending unin-- terruptedly from the top of the hollow body and extending uninterruptedly from said opposite lateral sides of the hollow body and terminating at a level below the stated level of the first-named septum, thereby providing a space within the upper interior of the hollow body for'the entrapment therein of air under pressure, the free surface of which and the stated two septa define a serpentine path of flow of the water under pressure, and opening means disposed at the top of the hollow body adjacent said remote end of the hollow body for affording upward outflow of the water from the stated serpentine path of flow.

' EDWARD S. CORNELL, JR. 

